According to doctors the risk of pregnancy off pre cum is high, so why isnt there so many cases of this or why isnt there any statistics? i mean girls have had sex during ovulation without protection.is it cause sperm count lower maybe in pre cum?

Your opening premise is wrong: few if any doctors say exposure to pre-ejaculate fluid (precum) is high risk for pregnancy. On rare occasions women report that sex without ejaculation led to conception (perhaps from precum), but usually they probably are wrong. Indeed there are very few sperm in pre-ejaculate fluid.

No- doctors who are knowledgeable about this do not say that. Pre-cum is the secretion of the glands lining the genital passageway which secrete precum. True precum has no sperms. Also not all sex results in pregnancy. The sperm can only fertilize the egg during ovulation period- generally. There is nothing absolute - there are exceptions to everything in medicine.